The incredible landscapes and mesmerizing backwaters of Kerala invite people in huge numbers all round the year. This God's Own Country, is blessed with magnificent beaches, soothing beaches, thrilling festivals, heritage sites, tremendous natural beauty, and awe-inspiring hill stations. But similar to some parts of India, Kerala experiences a tropical climate with humidity. For most parts of the year, the temperature remains around 33 degree centigrade. It is during the winter months (October-January) when the temperature drops down to around 21 degrees centigrade. Thus, the warm, moist, and tropical climate of Kerala recommends you to put on light cotton clothes. If you are traveling to Kerala during the monsoon season, you must take care of waterproofing and make arrangements for the same. Besides light cotton clothes/outfits, you must also carry hats, sunglasses, and sunscreen lotion to protect the skin from sun.
Foreign visitors can sometimes face prolonged staring or glances from the localites, even though there is no physical assault. There are locations where you can easily stroll around in a bikini, but it is recommended that you cover up and look decent to avoid embarrassing stares from the local people. Most places demand civilized dressing, similar to the dressing of the local men and women. Look around and you'll see all of them covering their body almost completely. And that's exactly, what they expect from their visitors, to maintain the dignity of the state. Nudity is strictly banned and not allowed in India, even if it is a private beach. Hence, women are not allowed to sunbath topless in any part of Kerala. As such, you need to step ahead and dress according to the sensibilities of the Indians to keep away from uncomfortable gazes. For those who cannot live without sunbathing, can do so inside the hotels, at Ayurvedic centers, and at locations where sunbathing in bikini is allowed. Especially beaches, like Kovalam, allow foreign tourists to indulge in sunbathing. Similarly, there are locations where a bikini can be sported without any inhibitions, while at other places, you need to be a little cautious.
Here is a brief write up on clothes to wear while traveling to Kerala.